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521.
Jelka Šuštar-Vozlič Katja Rostohar Andrej Blejec Petra Kozjak Zoran Čergan Vladimir Meglič 《Analytical and bioanalytical chemistry》2010,396(6):2031-2041
In order to comply with the European Union regulatory threshold for the adventitious presence of genetically modified organisms
(GMOs) in food and feed, it is important to trace GMOs from the field. Appropriate sampling methods are needed to accurately
predict the presence of GMOs at the field level. A 2-year field experiment with two maize varieties differing in kernel colour
was conducted in Slovenia. Based on the results of data mining analyses and modelling, it was concluded that spatial relations
between the donor and receptor field were the most important factors influencing the distribution of outcrossing rate (OCR)
in the field. The approach for estimation fitting function parameters in the receptor (non-GM) field at two distances from
the donor (GM) field (10 and 25 m) for estimation of the OCR (GMO content) in the whole receptor field was developed. Different
sampling schemes were tested; a systematic random scheme in rows was proposed to be applied for sampling at the two distances
for the estimation of fitting function parameters for determination of OCR. The sampling approach had already been validated
with some other OCR data and was practically applied in the 2009 harvest in Poland. The developed approach can be used for
determination of the GMO presence at the field level and for making appropriate labelling decisions. The importance of this
approach lies in its possibility to also address other threshold levels beside the currently prescribed labelling threshold
of 0.9% for food and feed. 相似文献
522.
Vinzenz Handrick Thomas Vogt Andrej Frolov 《Analytical and bioanalytical chemistry》2010,398(7-8):2789-2801
Phenylpropanoid polyamine conjugates are widespread in plant species. Their presence has been established in seeds, flower buds, and pollen grains. A biosynthetic pathway proposed for hydroxycinnamoyl spermidine conjugates has been suggested for the model plant Arabidopsis thaliana with a central acyl transfer reaction performed by a BAHD-like hydroxycinnamoyl transferase. A detailed liquid chromatography (LC)–electrospray ionization–mass spectrometry- and tandem-mass-spectrometry (MS/MS)-based survey of wild-type and spermidine hydroxycinnamoyl transferase (SHT) mutants identified more than 30 different bis- and tris-substituted spermidine conjugates, five of which were glycosylated, in the methanol-soluble fraction of the pollen exine. On the basis of characterized fragmentation patterns, a high-throughput LC–MS/MS method for highly sensitive HCAA relative quantification (targeted profiling) was developed. Only minor qualitative and quantitative differences in the pattern of bis-acyl spermidine conjugates in the SHT mutant compared to wild-type plants provide strong evidence for the presence of multiple BAHD-like acyl transferases and suggest a much more complex array of enzymatic steps in the biosynthesis of these conjugates than previously anticipated. 相似文献
523.
Structural properties of effective potential model by liquid state theories 总被引:1,自引:0,他引:1
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This paper investigates the structural properties of a model fluid dictated by an effective inter-particle oscillatory potential by grand canonical ensemble Monte Carlo (GCEMC) simulation and classical liquid state theories.The chosen oscillatory potential incorporates basic interaction terms used in modeling of various complex fluids which is composed of mesoscopic particles dispersed in a solvent bath,the studied structural properties include radial distribution function in bulk and inhomogeneous density distribution profile due to influence of several external fields.The GCEMC results are employed to test the validity of two recently proposed theoretical approaches in the field of atomic fluids.One is an Ornstein-Zernike integral equation theory approach;the other is a third order + second order perturbation density functional theory.Satisfactory agreement between the GCEMC simulation and the pure theories fully indicates the ready adaptability of the atomic fluid theories to effective model potentials in complex fluids,and classifies the proposed theoretical approaches as convenient tools for the investigation of complex fluids under the single component macro-fluid approximation. 相似文献
524.
We introduce the quadratic two-parameter eigenvalue problem and linearize it as a singular two-parameter eigenvalue problem. This, together with an example from model updating, shows the need for numerical methods for singular two-parameter eigenvalue problems and for a better understanding of such problems.There are various numerical methods for two-parameter eigenvalue problems, but only few for nonsingular ones. We present a method that can be applied to singular two-parameter eigenvalue problems including the linearization of the quadratic two-parameter eigenvalue problem. It is based on the staircase algorithm for the extraction of the common regular part of two singular matrix pencils. 相似文献
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Marjan Druovec Bojan A
ko Andrej Godina Tatjana Welzer 《Optics and Lasers in Engineering》2009,47(11):1131-1138
The paper presents research into line centre detection using a video positioning system, as part of a measuring system for line scale calibration. In the described approach, the video positioning system processes an image taken by a CCD camera to estimate the position of the observed line's centre. An important part of this research is also an analysis of line scale contamination's influence (scratches, dirt, usage, etc.) on line position determination. The outcome of the research is mathematical models that can be used as a base for developing a positioning algorithm. This algorithm is simple and adaptable to different types of line scales. It also includes a module for increasing the basic scale factor of the positioning as defined by the number of pixels in the CCD sensor, and a module for reducing the influence of contamination on positioning. 相似文献
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